The preferred gambit is different for expats and locals (those retiring here).

Expats: Can dissolve Pillars 2 and 3 when they leave, albeit restrictions for those returning to EU countries. Most probably smaller pension capital (only a few years contributions in CH). Unlikely prepared to wait several years to avoid clubbing. Not much benefit in splitting (also because of minimum tax rates).

Locals: Cannot dissolve before age 60 (some premature withdrawals permitted, e.g. starting own business, mortgage loans, etc.). Must dissolve latest at age 70. Pension plans convert to annual pension or capital at retirement 65. Always taxed according to rules of domicile Canton. Most likely to benefit from tax planning.